Just download HotSpot Shield. You can only use it for 3 GB of internet usage per month, but if you only use it for RS you won't run out lol.
EDIT: Now that I think of it, why would someone DDOS you, especially when you were helping them with something?
The only times they would really benefit from doing that, is if you were doing something dangerous on RS and would profit from your death. They won't know your RSN, you will be the one knowing theres lol (and there IP if they last logged on there acc from there network).
And now that I think of the keylogging bit, they can't keylog you just by knowing your IP lol.
But to each his own, you should have just said you wanted to be private/safe